( )和其自然特性是土地所具有的特性。
A.计划经济 B.社会经济 C.商品经济 D.市场经济
参考答案:B
石油沥青的牌号越大,则其( )
A.针入度越小 B.延度越小C.软化点越低 D.粘度越大
The students in Class Two played basketball against Class One yesterday, _______? [ ]
A. did they
B. didn't they
C. weren't they